Atkinson M W, Goldenberg R L, Gaudier F L, Cliver S P, Nelson K G, Merkatz I R, Hauth J C
Department of Obstetrics and Gynecology, University of Alabama at Birmingham, USA.
Am J Obstet Gynecol. 1995 Jul;173(1):299-305. doi: 10.1016/0002-9378(95)90218-x.